Automatic tube bender



May 25, 1965 R. G. OLSON AUTOMATIC TUBE BENDER 3 Sheets-Sheet 1 Filed Oct. 31, 1962 INVENTOR.

May 25, 1965 R. G. OLSON AUTOMATIC TUBE BENDER 3 Sheets-Sheet 2 Filed Oct. 31, 1962 INVENTOR. $512101! BY May 25, 1965 Filed Oct. 31, 1962 -R. G- OLSON AUTOMATIC TUBE BENDER 3 Sheets-Sheet 3 INVENTOR OTL/ United States Patent 3,184,949 AUTOMATIC TUBE BENDER Raymond G. Olson, Niles, 111., assignor to Ray Laboratories, Inc, a corporation of Illinois Filed Oct. 31,1962, Ser. No. 234,405

15 Claims. (Cl. 72-307) This invention relates generally to automatic tube benders, and more particularly to a novel substantially pneumatically operated tube bender which will automatically operate to bend a length of tubing in a serpentine or sinuous fashion.

The primary object of the present invention is to provide a novel tube bender arrangement capable of automatic operation.

It is a further object to provide a novel substantially pneumatically operated and controlled automatic tube bender.

It is a further object to provide a novel bending arm arrangement for a tube bender capable of bending a length of tubing in a serpentine fashion.

It isstill another object to provide novel means for controlling a pair of bending arms in a tube bender arrangement capable of bending a length of tubing in a serpentine fashion.

It is still another object to provide novel means substantially pneumatically operated and controlled for operating a pair of tube bender arms and for feeding a length of tubing to automatically bend the tubing in a predetermined serpentine fashion.

Other objects and features of the present invention will be apparent upon a perusal of the following specification and drawings in which:

FIGURE 1 is a top plan view of one embodiment of the invention;

FIGURE 2 is. a side elevational view of a portion of the structure shown in FIGURE 1 and taken along the line 2-2 of FIGURE 1;

FIGURE 3 is a top plan View of a portion of the structure shown in FIGURE 1 with the two bender arms operated to another position;

FIGURES 4 and 5 are views similar to FIGURE 3 but showing other operated positions of the bender arms;

FIGURE 6 is a side elevational view of a portion of the structure shown in FIGURE 1 and taken substantially along the line 6--6 of FIGURE 1;

FIGURE 7 is a top plan view of the rack shown in FIGURE 6;

FIGURE 8 is a side elevational view of the structure shown in FIGURE 6 and taken substantially along the line 88 of FIGURE 6; and

FIGURE 9 is a diagrammatic view of operating and control circuits for the present embodiment of the invention.

The present embodiment is the preferred embodiment, but it is to be understood that changes can be made in the present embodiment by one skilled in the art without departing from the spirit and scope of the present invention.

Generally, the present embodiment provides a tube bender construction which will automatically operate to bend a length of tubing in a serpentine fashion. The tubing shown in the drawings in rectangular in cross section and of the type commonly used in the construction of finned tube heat exchangers for air conditioning units. A pneumatically operated tubing feed device is used to feed the tubing to a pair of tube bending arms. Any suitable tube feeding device known in the art may be used. Suitable pneumatically operated tube feeding devices are manufactured by Power Control Products, Inc. of Vicksburg, Michigan. Such pneumatically operated tube feeding devices comprise a stationary jaw and a movable paw. The stroke of the movable jaw is ad- Bibifiih Patented May 25, I965 "ice justable to repeatedly feed .a predetermined length of tub-ing to the tube bending arm-s. After the movable jaw has gripped the tubing and delivered a predetermined length of tubing tothe tube bending arms through the stationary jaw, the stationary jaw operates to securely clamp the tubing against longitudinal movement and the movable jaw releases and is returned preparatory to again gripping and delivering the next succeeding predetermined increment-of tubing to the bending arms. The tube bending arms are carried on the upper end of a pair of shafts which are .j-ournaled to extend vertically downwardly through a table capable of supporting the tubing thereon particularly when the tubing has been fashioned in a serpentine fashion of a substantial plurality of parallel straight sections interconnected by curved end sections. The pair of bending arms are additionally carried for axial reciprocating movement. The lower end of each bending arm shaft is provided with an air cylinder which is operable to move the shaft axially downwardly. Each of those air cylinders is provided with a compressed coiled spring for biasing each bending arm shaft in the axially raised position.

The bending arm shafts are rotated by a gear rack which meshes with gear teeth carried on each shaft intermediate the ends thereof. The gear rack in turn is operated by an air cylinder through a lost motion linkage arrangement.

The bending arms are always rotated in unison and are always apart. A number of air and electrical circuits are connected to the tube feeding device, and associated with the tube bending arms and shafits, and the air cylinders cooperating therewith for operating and controlling the arrangement to produce automatic operation thereof.

In detail, the tube feed device is shown generally at 10 in FIGURE 1. The tube feed device 10 is fixed in cooperation with a table, a portion of which is indicated gene-rally at 11, so that the tub-ing is delivered in a sliding manner over the upper surface of the table 11. The tube feed device comprises a stationary jaw assembly 12, a movable jaw assembly 13 and a reciprocating air cylinder 14. The detailed construct-ion of the various parts of the tube feed device may take any suitable form known in the art. The stationary jaw 12 comprises a base member 15 on which is fixedly carried a stationary jaw member 16 and a clamping jaw member 17. The jaw members 16 and 17 define an open slot therebet-ween which will admit the tubing 18. The clamping jaw member 17 operates responsive to air pressures supplied through the air conduit 20 to clamp and securely hold the tubing 18 against the fixed jaw member 16.

The movable jaw 13 is similar in construction to the stationary jaw 12 and comprises a base member 21 upon which is carried a fixed jaw member 22 and a clamping jaw member 23. The base member 21 is slidably carried on some rail arrangement (not shown) which permits the movable jaw 13 to be moved in a reciprocating operation toward and away from the stationary jaw 12. The jaw members 22 and 23 also define a slot capable of receiving the tubing 18, and the clamping jaw member 23 is operated responsive to air pressures supplied to air conduit 24 to clamp the tubing 18 against the fixed jaw member 22. The movable jaw 13 is caused to reciprocate toward and away from the stationary jaw 12 by the reciprocating air cylinder 14. The piston rod 25 of the air cylinder 18 is connected to the base member 21 of the movable jaw 13. An air conduit 26 is connected into the rod end of the cylinder 14, and as shown in FIGURE 9, an air conduit 27 is connected into the head end of the air cylinder 14. Suitable means (not shown) is provided for adjusting the stroke of the air cylinder 14 to vary the incremental length of tubing 18 delivered to the table 11.

Valve means 34 and 35 shown in FIGURE 9 are provided for'proper operation of the tube feed device. Valve means 34 is operated by a solenoid 36, and valve means 34 controls the operation of the valve means 35 as indi cated by the dotted lines'37 in FIGURE 9. Valve means 34 is connected to a source of air under pressure 38 by an air conduit 49. Valve means 35 is connected to the source of air pressure 38 byan air conduit 41. Valve means 34 is also connected to air conduits 26 and 27 for the air cylinder 14. Valve means 35 is also'connected to conduits and 24, respectively delivering air to the stationary jaw 12 and the movable jaw 13. Under control of the solenoid 36, the tube feed device will operate to periodically deliver predetermined lengths of tubing 18 between and forwardly of the backup plates and 31 and the tube bending arms 32 and 33. This periodic feed of tubing 18 maybe described by beginning with operations of the valve means 34 and to release the stationary jaw 12, and to operate the movable jaw 13 to grip the tubing 18. These operations will be followed by an extension of the air cylinder 14 to move the tubing 18 through the released jaw members 16 and 17 of the stationary jaw 12, between the backup plates 30 and 31, and over the upper surface table. 11. When the air cylinder 14 has moved the movable jaw 13 to the limit of its forward stroke, the stationary jaw 12 will operate to securely grip the tubing 18, the movable jaw 13 will release the tubing 18, and the air cylinder 14 will retract preparatory to repeating the described cycle of operation. V The tube bending arms 32 and 33 are substantially mirror-images of each other. The tube bending arm 32 comprises a shaft 44 which is vertically carried through an openingin the table 11. The bending arm 33 similarly comprises a shaft 45 carried vertically through an opening in a table 11. The shafts 44 and 45 are spaced apart a distance substantially equal to the thickness of the tubing 18. The bending arm 32 further comprises a pad member 46 and a support arm 47. The support arm 47 is secured to the upper end of the shaft 44 and extends radially outwardly therefrom. The pad member 46 is secured to the underside and at the outer end of the support arm 47 and is carried in a substantially vertical position. The pad member 46 is provided with a'face plate 48 which is carried on the pad member 46 by a fastener 50. The rearward side of the faceplate 48 is provided with a vertically disposed curved shoulder which projects into a vertically disposed curved channel in the forward side of the pad member 46. The-surfaces of the pad member 46 extending from the curved channel to each end thereof are slightly angled away from the face plate 48 to permit a slight rocking movement of the face plate 48 about a vertical axis. The fastener 58 is sufiiciently loose to permit this movement. This slightly permitted rocking movement of the face plate 48 enables the face plate 48 to firmly engage one side of the tubing 18 in planar contact. The face plate 48 has a height which is at least equal to the height of the tubing 18. The longitudinal axis of the face plate 48 is positioned by the pad member 46 and the support arm 47 so that the face plate 48 engages the tubing 18 on the side opposite from the side engaged by the shaft 44. This arrangement may easily be seen in FIGURE 4.

The bending arm 33 is similar in construction to the bending arm 32, having a pad member 52 which is secured to a support arm 53, which in turn is secured to the upper end of the shaft 45. i A face plate 54 is also provided. and is connected to the pad member 52 by e fastener 55. The face plate 54 also always engages the side of the tubing 18 opposite from the side engaged by the shaft 45.

The shafts 44 and 45 are supported for pivotal and axial movement by a pair of bearing assemblies 57 and 58. Therbearing assembly 57 is secured to the underside of the table 11 by fasteners 60 and is provided with a pair of spaced apart holes carrying bearings 61 for the shafts 44 and 45. The bearing assembly 58 is secured to a vertically disposed support plate 62 by fasteners 63. The support plate 62 is secured to the underside of the table 11. The bearing assembly 58 is provided with bearings 64 carried in openings therethrough for the shafts 44 and 45.

The lower end of the shaft. 44 is provided with an air cylinder-assembly 65 for axially moving the shaft 44 upwardly and downwardly relative to the table 11. The shaft 45 is provided with a similar air cylinder assembly 66. Y The air cylinder assembly 65 is provided with a piston rod 67 connected to a piston head 68 carried in the cylinder portion. A compressed coiled spring 70 is carried in the assembly 65 between the lower end thereof and the piston head 68 to bias the piston rod 67 to the extended position. The upper end of the piston rod 67 is carried in a coupling member 71 which in turn is connected to the lowerendof-the' shaft 44. The coupling member 71 may be of any suitable type known in the art and operates to connect the piston rod 67 to the shaft 44 while permitting the. shaft 44 to rotate relative to the piston rod 67. The .cylinder portion of the assembly 65 is secured to the support plate 62. The rod end of the assembly 65 is provided with an air conduit 72. Thus it maybe seen that the shaft 44 and the tube bending arm 32 carried thereon are maintained in the raised position by the coiled spring 70-and are lowered to bring the face plate 48 in thehorizontal plane of the tubing 18 by the application of air under suitable pressure to conduit 72 of the assembly 65.

The air cylinder assembly 66 is similarly constructed to assembly 65, comprising a piston rod 74 connected to a piston head 75 at the lower end thereof and to a couplingassembly 76 at the upper end thereof. A compressed coiled spring 77 is carried in the cylinder portion between the piston head and the lower end of the assembly 66. The rod end of the assembly 66 is provided with an'air conduit 78. FIGURE 8 shows a pair of fasteners 80 securing the assembly 66' to the vertical supporting plate 62. The lowered position ofthe shaft 45 in FIGURE 6 occurs when air under suitable pressure is delivered to conduit 78.

The shafts 44 and 45 are pivoted by a gear rack 81. The top plan .view of the gear rack 81 showing the gear teeth formed on one side thereof may be seen in FIG- URE 7. The gear rack is adapted to engage gear teeth on the shafts. 44-and 45. In the present embodiment, suitable gear teeth are cut into the shafts 44 and 45, and as may beseen in FIGURE.6, the gear teeth 82 on the shaft 44 extend for a considerable length of the shaft 44. The gear teeth 83 on the shaft 45 extend .for a considerable length of the shaft 45.. This construction permits a driving engagement between the gear teeth 82 and 83 and the gear rack'81 inany raised or lowered position of the shafts 44:and 45.

The gear rack 81 is slidably carried in four brackets 84. The brackets 84 are secured to the support plate 62 by fasteners 85 and position the gear rack 81 to engage the gear teeth 82. and 83 respectively of the shafts 44 and 45. It may be seen that because the gear rack 81 engages the gear teeth of both shafts 44 and .45, those shafts will always be pivoted in unison. The relative rotated or pivoted positions of the shafts 44 and 45 are such that the bending arms-32 and 33 are substantially apart. In other words, when'the bending arm 32 is in a rotated position representing a completed bend, the bending arm 33 is in a rota-ted position for the start of 'a bend. This arrangement is shown in FIGURE '1.

The gear rack 81 is operated by a reciprocating air cylinder 86. The air cylinder'86 comprises a cylinder portion which is secured to the support plate 62 by fasteners 87, and a pistonhead 88 connected to a piston rod 98. An air conduit 91 is provided at the rod end of the cylinder, and an air conduit 92 is provided at the head end of the cylinder. The gear rack 01 is formed with a hole extending longitudinally therethrough. The piston rod 90 of the air cylinder 86 extends through the hole in the gear rack 81. The diameter of the piston rod 90 is such that the rod 90 is freely slidable through the gear rack 81. A pair of adjustable stops 93 and 94 are secured to the piston rod 90 at each end of the gear rack 81. When the air cylinder 86 is extended, the stop 94 will engage one end of the gear rack 81 to move the gear rack 81 to rotate the shafts 44 and 45 in one direction. When the air cylinder 86 is retracted, the stop 93 will engage the other end of the gear rack 81 to move the gear rack 81 to rotate the shafts 44 and 45 in the opposite direction. The spacing between the stops 93 and 94 is greater than the length of the gear rack 81 for a reason which will be described below.

An understanding of the manner in which the bending arms 32 and 33 bend a length of tubing 18 in a serpentine fashion can be gained from a consideration of FIGURES 1, 3, 4 and 5. Assuming the initial position as shown in FIGURE 1, and that the bending arm 32 is in the raised position while the bending arm 33 is in the lowered position, it may be seen that if the shafts 44 and 45 are rotated in a clockwise direction as viewed in FIGURE 1 through an angle of approximately 183, the tubing 18 will be bent by the bending arm 33 about the shaft 45 to a position against the backup plate 31 such as shown in FIGURE 3. The reason for an approximate bending angle of 183 rather than180 is that most materials of which the tubing 18 may be formed will exhibit the property of slightly restoring after the bending operation. Thus by bending through an angle of approximately 183, the tubing will restore to a bent position of approximately 180 upon the release of bending pressure from the tubing 18. To achieve a bending angle of approximately 183, the backup plates 30 and 31 are formed so that the sides thereof which engage the tubing 18 in the bending operation are angled slightly rearwardly in the direction of bending. The backup plates 30 and 31 are secured to the upper surface of the table 11 by fasteners 95 with the backup plate 30 extending rearwardly from the shaft 44 on one side of the delivered tubing 18. The backup plate 31 is positioned to extend rearwandly of the shaft 45 on the other side of the delivered tubing 18. The spacing between the backup plates 30 and 31 may be sub stantially equal to the thickness of the tubing 18 although in the present embodiment that spacing is shown as slightly larger than the thickness of the tubing 10.

Continuing from the view shown in FIGURE 3, it may next be assumed that the arms 32 and 33 are both in the raised position, and the tube feed device may then be operated to advance the tubing from the position shown in FIGURE 3 to that shown in FIGURE 4-. Assuming next that the bending arm 32 is lowered while the bending arm 33 remains in a raised position, it may be seen that upon a counterclockwise rotation of the shafts 44 and 45, the bending arm 32 will bend the tubing 18 about the shaft 44 to a position against the backup plate 30 such as shown in FIGURE 5. Bending arm 32 may then be raised and the tube feed device operated to again advance the tubing 18 a certain predetermined amount. The bending arm 33 may then be lowered with the face plate 54 thereof engaging one side of the tubing 18, and as in FIGURES 1 and 3, the bending arms may be pivoted in a clockwise direction with the bending arm 33 again bending the tubing 18 to a position against the backup plate 31. It should be noted that upon completion of the described bending operation, the bent tubing will have two more sinuations than shown in FIGURE 3.

FIGURE 9 in diagrammatic view shows the various control elements and circuits for operating the bender arrangement of the present embodiment in the above described manner. The air conduit '72 of the air cylinder assembly 65 is connected to one port of a pressure operated valve 97. The pressure operated valve 97 may be of any suitable type known in the art and is provided with a pressure port to which one end of an air conduit 98 is connected and three valve ports, one which is an exhaust port and is designated 100, the second to which the conduit 72 is connected, and the third to which a conduit 101 is connected. The pressure operated valve 97 is so constructed that when no air under pressure is applied to conduit 93, conduit 101 is connected to conduit 72 through the valve, and when air under pressure is applied to conduit 98 the valve operates to block conduit 101 and to connect conduit 7.2 to the exhaust port 100. The other end of conduit 98 is connected into conduit 91 intermediate the ends thereof. Conduit 91 has previously been described as connected at one end thereof to the rod end of the air cylinder 86. The other end of the conduit 91 is connected to a port 102 of a solenoid operated air valve 103. The other end of conduit 101 is connected into an air conduit 104 intermediate the ends thereof. One end of conduit 104 is connected into conduit 20 which has previously been described as connected to the stationary jaw 12. The other end of conduit 104 is connected to a port of a pressure operated valve 105.

The pressure operated valve 105 is substantially identical in construction to valve 97, and comprises a pressure port to which one end of an air conduit 106 is connected and three valve ports. One of the valve ports is an exhaust port and is designated 107. The second of the valve ports is connected to conduit 78 which has previously been described as connected to the air cylinder assembly 66, and the third valve port is connected to air conduit 104. The pressure operated valve 105 is so constructed that when no air under pressure is applied to conduit 106, conduit 104 is connected to conduit 70 through the valve, and when air under pressure is applied to conduit 106, the valve will operate to block conduit 104 and to connect conduit 70 to the exhaust port 107. From the foregoing it may be seen that whenever the valve assembly 35 is operated to deliver air under pressure through conduit 20 to operate the stationary jaw 12 of the tube feed device, air under pressure will also be delivered to either one of the air cylinder assemblies 65 or 66 dependent upon whether the pressure operated valve 97 or 105 associated therewith is operated.

The end of conduit 106 opposite from that end which is connected into the pressure port of the pressure operated valve 105 is connected into conduit 92. Conduit 92 has previously been described as connected into the head end of the air cylinder 86. Conduit 92 is also connected to port of the solenoid operated valve assembly 103. In addition to ports 102 and 108, the valve assembly 103 is provided with a port 110 and an exhaust port 111. A pair of solenoids 112 and 113 are provided for operation of the valve assembly 103. The valve assembly 103 may be of any suitable type known in the art and the construction thereof is such that when solenoid 113 is operated port 100 is connected to port 111'and port 110 is connected to port 102 through the valve, and so that when solenoid 112 is operated port 110 is connected to port 108 and port 102 is connected to port 111 through the valve. Port 110 is connected to one end of an air conduit 114, the other end of which is connected to conduit40 which has previously been described as connected between the source of air pressure 38 and the valve assembly 34. Thus it may be seen that the source of air pressure is connected to port 110 of the valve assembly 103. It may further be seen that when solenoid 113 is operated air under pressure is delivered to the rod end of the air cylinder assembly 86 through conduit 91 and to the pressure operated valve 97 through the conduit 98. The pressure operated valve and the head end of the air cylinder assembly 86 are connected to exhaust through conduits 106 and 92, and ports 100 and 111 of valve 103. It may also be seen that when solenoid 112 is operated, air under pressure is delivered to the head end of the air cylinder assembly 86 and the pressure operated valve 105, while the rod end of'the air cylinder assembly 86 and the pressure operated valve 97 are connected to exhaust.

The solenoids 112 and 113 are operated by a switch assembly 115 which is carriedon the base 15 of the stationary jaw 12. The switch assembly 115 is operated by an arm assembly 116 carried on the base member 21 of the movable jaw 13. The switch assembly 115 may be carried on a stationary portion of the tube feed device, however the arrangement of the switch assembly 115 and the operating arm assembly 116 must be such that the switch assembly 115 is operated each, time the movable propriately spring biased armature 120. The armature 120is carried between a pair of fixed switch contacts. 121 and 122. The various described members of the switch assembly 115 and the switch operating arm assembly 116 are relatively aligned and positioned so that at the end of each forward stroke of the movable jaw 13, the operating arm assembly 116 will engage the ratchet wheel 117 to rotate the ratchet Wheel 117 an amount suflicient to rotate the cam member 118 to move the armature 120 from engagement with either one lobe or depression of the cam member 118 to the respective next depression or lobe thereof. When the armature 120 engages one of the lobes of the cam member 118, the armature makes electrical contact with the switch contact 122, and when the armature 120 engages one of the depressions in the cam member 118, the armature 120 makes contact with the switch contact 121. Switch contact 121 is connected to one end of an electricalconductor 123. The armature 120 is connected to-one end of an electrical conductor 124, and the switch contact 122 is connected to one end of an electrical conductor 125. Thus it may be seen that at the end of each forward stroke of the movable jaw 13, an electrical circuit between conductor 124 andone of the pair 'of conductors 123 and 125 is alternately completed.

A source of electrical power 126 is provided for the solenoids 112 and 113. One side of the source ofpower 126 is connected to conductor 124 and the other side of the source of power 126 is connected in parallel over an .obvious circuit to one side of each of the solenoids 112 and113. The other side of solenoid 112 is connected to conductor 125, and the other side of the solenoid 113 is connected to conductor 123. These described circuits provide for the alternate operation of the solenoids 112 and 113 responsive to operations of the switch assembly 115.

The remaining'structure of the presentembodiment of the invention comprises a pair of switches 128 and 130 for operating the solenoid 36. The switches 128 and 130 are normallyopen, single-pole, single-throw switches. Switch 128 .is carried on the table .11 immediately rearwardly of the backup plate and at a position such that the switch "128 will be operated to close the contacts thereof by the tubing 18 in abent position such as shown in FIGURE 5. The switch 130 is carried on the table 11 immediately rearwardly of the backup plate 31 and .at a position such that the switch 130 is operated by the tubing 18 when bent to a position such as shown in FIG- URE 3. The contacts of switch 128 are connected to a pair of conductors 131 and 132. The contacts of switch 130 are connected to a pair of conductors 133 and 134.

Conductors 133 and 131 are connected in parallel to one one side of the tubing end of aconductor 135. Conductors 134 and 132 are connected in parallel to one end of a conductor 136. The other end of conductor 135 is connected to one side of a source of electrical power 137. The other side of the source of electrical power 137 isconnected to one side of the solenoid 36. The other end of conductor 136 is connected to the other side of thesolenoid 36. From the foregoing it may be seen that solenoid 36 is operated when either switch 128 or 130 is operated.

The operation of the present embodiment of the invention is hereinafter described in order that the invention may be more readily understood. Assuming that the valve 35 is operated so that the stationary jaw 12 is operated to firmly grip theltubing 18, air under pressure will also be available at the pressure operated valves 97 and 165. The operated positionof the valve 35 will also be such that the moving jaw 13 will be released; At the same time, the valve 34 willbe in an operated position to supply .air under pressure to the rod end of the air cylinder 14 while exhausting air from the head end thereof. Thus the stationary jaw 12 is gripping the tubing 18 while the movable jaw 131s returning to the rearward position. Assuming further that the switch assembly has been operated to the position shown in'FIGURE 9, with the circuit for solenoid 112. completed, under this condition the pressure operatedvalve 105 has been operated to deliver air under. pressure to the rod end of the air cylinder assembly 66 and that cylinderhas operated to lower the bending arm '33 in bending position against 18 as in FIGURE 1. Since air under pressure has been delivered to the pressure operated valve 165, air under. pressure has also been deliveredto the head end of .the air cylinder assembly 86 while the rod end thereof is connected to exhaust. Assuming further that the air cylinder assembly 361135 extended to the position wherein the stop 34 engages one end or" the gear rack 81. .The next operation that occurs will be a further extension of the air cylinder assembly 86 to move the gear rack 81 to rotate the shafts 44 and 45 from a position such as shown in FIGURE 1 to a position such as shown in FIGURE 3 with a consequent bending of the tubing 18 to a position such as shown in FIGURE 3. When the tubing 18 engages the switch at the end of the bend, the switchliihwill operate to complete a circuit for operation of the solenoid 36. The solenoid 36 in operating will shift thevalves 34 and 35 into the otherv operated positions thereof. The valve 34 includes a time delay feature so that before the air under pressure at therod end of the cylinder 14 is shifted to the head end thereof, the valve 35 will operate to cause the operation of the moving jaw 13 .to firmly grip the tubing 18 and the restoration of the stationary jaw 12 to release the tubing 18. After these operations of the jaws 12 and 13, the valve 34 will operate to direct air under pressure to the head end of the air cylinder assembly 14 while exhausting air from the rod end thereof. It should be noted that when the valve 35 is operated to restore the stationary jaw 12, the removal of airunder pressure from conduit 20 also caused the air cylinder" assembly 66 to return to'the normal .extendedyposition under the influence of the compressed coil spring 77, even though at this point the valve 105 remains operated. Thus at this point in the operation, both bending arms 32 and33 are in the raised position. The air cylinder assembly 14 will then extend to move the'movable jaw'13 on the forward stroke thereof. The moving jaw 13in moving forwardly will advance the tubing 18 from a position such as shown in FIGURE 3 to a position such as shown in FIGURE 4.

At the end of the forward stroke of the tube feed device, the valves .34 and 35 will be automatically operated by means (not shown) which .will cause the stationary jaw 12 to operate to firmly grip the tubing 18 and the movable jaw 13 to restore releasing the tubing 18. Again, the valve .34 does not operate to reverse the direction of air flow to the air cylinder assembly 14 until after a certain time delay. With the operation of the valve 35 at the end of the forward stroke of the movable jaw 13, the switch assembly 115 is operated by the operating arm 116. This operation of the switch assembly 115 will break the previously described circuit for solenoid 112 and will complete a circuit for the energization of solenoid 113. Solenoid 113 will operate the valve 103 to direct air under pressure to the rod end of the air cylinder assembly 86 while connecting the head end thereof to exhaust. With the application of air under pressure to the rod end of the air cylinder assembly 86, air under pressure is also delivered through conduit 98 to operate the pressure operated valve 97. Thus it may be seen that with the operation of the stationary jaw 12 and the pressure operated valve 97, air under pressure is delivered to the air cylinder assembly 65. Air cylinder assembly 65 will then operate to move the shaft 44 and the bending arm 32 downwardly in a bending position against the tubing 18. At this point it must be remembered that when the bending arm 33 was moved to bend the tubing 18 from the position shown in FIGURE 1 to that shown in FIGURE 3, the bending arm 32 was simultaneously moved from the position shown in FIGURE 1 to that shown .in FIGURE 3. It should further be noted that upon the advancement of the tubing 18 from the position shown in FIGURE 3 to that shown in FIGURE 4, the release of the switch 130 by the tubing 18 caused the switch 130 to open restoring the solenoid 36. The restoration of the solenoid 36 has no effect upon the operation of the valves 34 and 35, the solenoid 36 being effective only upon the energization thereof.

The next operation that will occur will be a retraction of the air cylinder assemblies 86 and 14. The amount of free travel of the stop 93 before engaging the end of the gear rack 81 insures the complete lowering of the bending arm 32 before the gear rack 81 is moved to begin a bending operation. When the stop 93 engages the gear rack 81, the shafts 44 and 45 and the bending arms 32 and 33 will be rotated with the bending arm 32 bending the tubing from a position such as shown in FIGURE 4 to a position such as shown in FIGURE 5, and with the bending arm 33 simultaneously returning to the position shown in FIGURE 5 for making a subsequent bend. While the bending operation occurs, the retraction of the air cylinder assembly 14 will have brought the moving jaw 13 to the end of the rearward stroke thereof.

Upon completion of the bend shown in FIGURE 5 the tubing 18 will engage and operate the switch 128. The switch 128 in operating will complete a circuit for the energization of the solenoid 36. The solenoid 36 will again operate to operate the valves 34 and 35. Valve 35 will operate to operate the movable jaw 13, release the stationary jaw 12 and remove the air under pressure from the air cylinder assembly 65 permitting the coiled spring 70 therein to raise the shaft 44 and the bending arm 32. After the time delay, valve 34 will operate to cause the air cylinder 14 to extend moving the movable jaw 13 on the forward stroke thereof to advance the tubing 18 preparatory to another bending operation. As the tubing 18 advances, switch 128 will be released and solenoid 36 will restore. At the end of the forward stroke of the movable jaw 13, the valves 34 and 35 will again be operated by means (not shown) to operate the stationary jaw 12, release the movable jaw 13, and apply air under pressure to the pressure operated valve 105. The switch assembly 115 is again operated by the operating arm 116, and the cam member 118 will again be rotated so that one of the lobes thereof engages the armature 129. Solenoid 113 will restore and solenoid 112 will be operated, and as previously described another bending operation will occur by the bending arm 33 while the air cylinder assembly 14 is retracted to restore the movable jaw 13 to its rearward position.

The described cycles of operation will automatically reoccur to bend a length of tubing in a serpentine fashion.

Particular note should be made of one feature of the combination of the tube feed device with the tube bending arrangement, and that feature is the firm gripping of the tubing 18 by the stationary jaw 12 in the manner of a vise during a bending operation. The stationary jaw 12 must not permit the tubing 18 to slip while .it is being bent as any slippage will cause an imperfect bend.

Having described the invention what is considered new and desired to be protected by Letters Patent is:

1. In a tube bending arrangement, a pair of tube bending arms, means rotatively carrying said bending arms for cooperation with a length of tubing, means for substantially simultaneously rotating said tube bending arms to bend said tubing with one of said arms and to position the other of said arms preparatory to bending when said pair of arms are rotated in one directionand to bend said tubing with said other of said arms and to position said one of said arms preparatory to bending when said pair of arms are rotated in the opposite direction.

2. In a tube bending arrangement, a pair of tube bending arms, tube clamping means for securely holding a length of tubing with one end of said tubing extending therefrom, means rotatively carrying said bending arms for cooperation with the extending end of said tubing, means for substantially simultaneously rotating said tube bending arms to bend said extending end of said tubing with one of said arms and to position the other of said arms preparatory to bending when said pair of arms are rotated in one direction and to bend said tubing with said other of said arms and to position said one of said arms preparatory to bending when said pair of arms are rotated in the opposite direction.

3. In a tube bending arrangement as defined in claim 2, means for momentarily releasing said clamping means, and means for advancing said length of tubing a certain amount through said clamping means when said clamping means is released.

4. In a tube bending arrangement, a pair of shafts, a pair of tube bending arms, each of said tube bending arms carried on one of said shafts to extend radially outwardly therefrom, each of said shafts having a curved surface for bending tubing thereabout, said curved surfaces being spaced apart a distance sufficient to admit a length of tubing therebetween, and means for substantially simultaneously rotating said shafts to bend said tubing about one of said curved surfaces with one of said arms and to position the other of said arms preparatory to bending.

5. In a tube bending arrangement, a pair of shafts, a pair of tube bending arms, each of said tube bending arms carried on one of said shafts to extend radially outwardly therefrom, each of said shafts having a curved surface for bending tubing thereabout, said curved surfaces being spaced apart a distance sufiicient to admit a length of tubing therebetween, means for substantially simultaneously rotating said shafts to bend said tubing about one of said curved surfaces with one of said arms and to position the other of said arms preparatory to bending when said shafts are rotated in one direction and to bend said tubing about the other of said curved surfaces with said other of said arms and to position said one of said arms preparatory to bending when said pair of shafts are rotated in the opposite direction.

6. In a tube bending arrangement, a pair of shafts, a pair of tube bending arms, each of said tube bending arms being carried on one of said shafts to extend radially outwardly therefrom, each of said shafts having a curved surface for bending tubing thereabout, tube clamping means for securely holding a length of tubing with one end of said tubing extending therefrom, means rotatively carrying said shafts on opposite sides of the extending end of said tubing with said curved surfaces being spaced apart a distance sufficient to admit said extending end of said tubing therebetween, means for substantially simultaneously rotating said shafts to bend said extending end of said tubing about one of said curved surfaces with one of said arms and to position the other of said arms preparatory to bending when said shafts are rotated in one direction and to bend said extending end of said tubing about the other of said curved surfaces with said other of said arms and to position said one of'said arms preparatory to bending when said pair of shafts are rotated in the opposite direction.

7. In a tube bending arrangement as defined. in claim 6, means for momentarily releasing said clamping means, and means for advancing said length of tubing a certain amount through said clamping means when said clamping means is released.

8. In a tube bending arrangement as defined in claim 7, and means for controlling said means for substantially simultaneously rotating said shafts, said means for momentarily releasing said clamping means, and said means for advancing said length of tubing, to bend said length of tubing in a serpentine fashion.

9. In a tube bending arrangement, a horizontally disposed table surface, a pair of shafts rotatively carried through said surface in a parallel spaced apart relationship to each other, a pair of tube bending arms, each of said tube bending arms carried on oneof said shafts above said surface to extend radially outwardly and downwardly from said shafts, means for vertically reciprocating said shafts to raise the depending portion of the tube bending arms thereof above said surface and to lower said depending portions substantially to said surface, a curved surface carried about each of said shafts for bending tubing thereabout, each of said curved surfaces being positioned in substantial horizontal alignment with the depending portion of the associated tube bending arm in the lowered positions of said shafts, said curved surfaces further being spaced apart a distance sufficient to admit a length of tubing therebetween, and

fashion.

11. In a tube bending arrangement, a horizontally disposed table surface, a pair of shafts rotatively carried through said surface in a parallel spaced relationship to each other, a pair of tube bending arms, each. of said tube bending arms being carried on one of said shafts above said surface to extend radially outwardly and downwardly from said shafts, means for Vertically reciprocating said shafts to raise the depending portion of the tube bending arms thereof above said surface and to lower said depending portions substantially to said surface, a curved surface carried about each of said shafts for bending tubing thereabout, each of said curved surfaces being positioned in substantial horizontal alignment with the depending portion of the associated tube bending arm in the lowered positions of said shafts, said curved surfaces further being. spaced apart a distance sufficient to admit a length of tubing therebetween, and means for substantially simultaneously rotating said shafts to bend said tubing about one of said curved surfaces with one of said arms in a lowered position and to position the other of said arms preparatory to bending when said shafts are rotated in one direction, and said other of said arms in a lowered position bending said tubing about the other of said curved surfaces and said one of said arms is positioned preparatory to bending when said pair of shafts is rotated in the opposite direction.

12. In a tube bending arrangement as defined inclaim .11, and means forfeeding a certain predetermined length of tubing between said curved surfaces and in cooperation with said bending arms.

13. In a tube bending arrangement as defined in claim 12, tube clamping means carried between said means for feeding said tubing and said curved surfaces to securely hold said tubing against lengthwise shifting when said tubing is bent.

14. In a tube bending arrangement as defined in claim 13, and means for momentarily releasing said clamping means during the operation of said means for feeding said tubing.

15. In a tube bending arrangement as defined in claim 14, and means for controlling said means for substantially simultaneously rotating the tube bending arms, said means for feeding said tubing, and said means for momentarily releasing said clamping means, to bend said length of tubing in a serpentine fashion.

References Cited by the Examiner UNITED STATES PATENTS 1,699,412 1/29 Thompson et al.

2,143,416 1/ 39 Jespersen.

2,453,868 11/48 Shaw 153-46 2,454,290 11/48 Payne 15346 2,565,940 8/51 Armstrong et a1. 153-45 CHARLES W. LANHAM, Primary Examiner.

WILLIAM J. STEPHENSON, Examiner. i 

1. IN A TUBE BENDING ARRANGEMENT, A PAIR OF TUBE BENDING ARMS, MEANS ROTATIVELY CARRYING SAID BENDING ARMS FOR COOPERATION WITH A LENGTH OF TUBING, MEANS FOR SUBSTANTIALLY SIMULTANEOUSLY ROTATING SAID TUBE BENDING ARMS TO BEND SAID TUBING WITH ONE OF SAID ARMS AND TO POSITION THE OTHER OF SAID ARMS PREPARATORY TO BENDING WHEN SAID PAIR OF ARMS ARE ROTATED IN ONE DIRECTION AND TO BEND SAID 